Using the node signatures, we calculate the topological difference between each node \(g \in G\)  and \(h \in H\) , according to the formula described in [1]}. In keeping with the flexibility of the original formula, we include a parameter \(\alpha \) , such that the topological distance \(T_{i,j} = \alpha \cdot S_{i,j} + (1 - \alpha ) \cdot N_{i,j}\) , where \(S_{i,j}\)  represents the difference in node signatures between nodes \(i\)  and \(j\) , and \(N_{i,j}\)  represents the difference in degree between the nodes \(i\)  and \(j\) . It is recommended to use the default \(\alpha = 1\) . We store the resulting values in the topological cost matrix \(T\)  whose computation has complexity \(O(|G||H|)\) .
